Fruit weight is a critical trait in many fruit and vegetable crops. Tomato (Solanum lycopersicum) is one of the most important crops in the world. Its fruit weight is a quantitatively inherited character that is controlled by many loci. Till now, the genes for two tomato fruit weight loci, fw2.2 and fasciated, have been cloned. In this study, we identified the fw11.3 locus on the bottom of chromosome 11 by the analysis of the S. lycopersicum cv. Howard German BC1F5 population in 2008. Progeny test in 2009 confirmed the QTL analysis result and narrowed the fw11.3 locus to about 500kb region based on the position of the marker on SL2.40ch11 (http://solgenomics.net/). Progeny test in 2010 and 2011 narrowed the fw11.3 locus to a 14kb region comprised of 4 predicted genes. Gene action analysis of fw11.3 locus indicates that the mutant allele is partially dominant over the wild allele.